Ore concentration.



G. A. CHAPMAN.

ons ooNoENTRATI'oN.

APPLIOATIOI- FILED MAY 8, 1913.

A Patented July 7, 1914,

lUNITED STATES PATENT OFFICE.

GEORGE A. CHAPMAN, 0F LONDON, ENGLAND, ASSIGNOR TO MINERALS SEPARATION, LIMITED, OF LONDON, ENGLAND, A. CORPORATION OF ENGLAND.

ORE CONCENTRATION.

Specification of Letters Patent.

Patented July '7, 1914.

To all whom t may concern: 1

.Be it known that I, GEORGE A. CHAPiuaN, a subject of the King of England, residing at London, England, have invented a certain new and useful Improvement in Ore Concentration, of which the following is a specification, reference being had therein to the accompanying drawings, forming part thereof.

This invention consists in improvements in or relating to ore concentration and has particular reference to the concentration of ores by flotation. Hitherto in the concentration of ores by flotation it has been the common practice to mix the powdered ore with about four times its weight of water and in' most instances to add to the pulp a small quantity of sulfuric acid (say 1% on the weight of the ore) and also to add to the pulp a very small proportion of either an immiscible oily agent, such as oleic acid, Texas fuel oil, etc., or of a soluble mineral frothing agent, such as phenol, cresol,

.amid-alcohol, amyl-acetate, etc., all as described, for example, in prior United States Patents No. 835,120 of November 6, 1906, No. 955,012 of April 412, 1910, and No. 962,678 of June 28, 1910, and British Patent- No. 21,857 of 1910. It has also been common practice to utilize in the above processes mixtures of different mineral frothing agents, both oily or immiscible and soluble. These processes have usually been carried on at temperatures varying from atmospheric rteniperaftiires up to say 60 centigrade, o1; even higher. As stated in these earlier `patents, the conditions most suitable 'and economical for the treatment of a. particular ore have been best determined by simple preliminary trials. Y

' It has heretofore been proposed to agitate the water with one or more agents known as modifying agents, such as oil of eucalyptus,

phenol, cresol, amyl-alcohol, amyl-acetate, wood tar oil, wood alcohol, and the like, and mixtures containing them, before the agitation of the ore with the water, and such preagitation with one or more modifying agents has been found to improve the recovery of concentrates or the or both. v

In the course of careful grade of the concentrates investigations on l* certain ores, it has been discovered that, if

the ore is groundwith water containing a modifying agent, there are many substantial improvements in efficiency and economy in the process of concentrating ores. For example, first, the newly exposed surfaces of the mineral are brought into contact with the water containing the modifying agent at the moment of the exposure of these surfaces; second, the power necessarily consumed in the work of grinding the ore ad ditionally effects the agitation of the water containing the modifying agent, and this in contact with freshly ground ore; third, the output of the grinding process may be increased, since the freshly ground particles, as soon as they are brought into condition for floating, may be floated or carried off with the overflow 4or outflow of water,

and thus automatically the mineral particleswill flow away from the grinding stage of the process as soon as they are in floatable condition; fourth, a recovery by separation of floating particles may be had immediately following s'uch a grinding operation; fifth, the ore pulp from the grinding operation .may be delivered to agitation-froth apparatus and there subjected to agitation and beating in of air andsep'aration of the agitation-froth by flotation, usually with the addition of a frothing agent, and greatly increased recoveries of mineral obtained in the floating froth or higher grades of concentrates, or both increase in recovery and in grade may be obtained; sixth, the agitationfroth process may be carried on at ordinary atmospheric temperatures and, indeed, in some instances, at a temperature so low that the froth, when produced, is frozen; and, seventh, the agitation-froth process may be carried on withoutthe use of any mineral acid, such as sulfuric acid.

In carrying out this invention in practice, the best results have been obtained by first subjecting the ore to a primary grinding, either wet ordry, and thereafter subjecting the partly crushed ore with water containing the modifying agent, to a secondary or final grinding, in which the ore is ground in contact with the water containing the modifying agent, and the water containing the.

modifying agent is agitated. The ore as thus ground with'water containing ajmodifying--agent may be delivered to an apparatus suit/able for carrying out the agitationfroth process, and then .subjected to that process. The following is an example of the application of this invention: j

A chalcocite ore containing 1.80 per cent. of copper was subjected to regrinding or dfinal grinding with water containing, as the modifying agent, cresol inf-.the proportion of 0.05 per cent. on the ore. The finely ground ore and water were delivered to an agitation-froth apparatus `and in the first mixer a frotliing agent was fed into the pulp consisting of American turpentine in the proportion of 0.05 per cent. on the ore. The concentrates delivered from the agitation-froth apparatus assayed 31.80 per cent. of copper and showed a recovery of 92.00 per cent. of copper.

The accompanying drawing illustrates diagrammatically ythe arrangement of apparatus which was employed in the example above given and-which is well adapted for carrying out my invention in practice. This drawing shows a vertical longitudinal section of a conical mill and a transverse vertical section of an apparatus for carrying out the agitation-froth process.

`The mill shown in the drawing is the well known Hardinge conical mill wherein the material to be ground is subjected to grinding action, preferably of. pebbles or balls 1, in a conical chamber 2 rotated on a nearly horizontal axis`at such speed as will assure.

effective grinding. The slight variation from `horizontal position convemently 10'- Vcates the outlet 3 at a somewhat lower position than the inlet 4, thus assuring an automatic discharge of the finely groiind ore. Coarse ground ore from a primary grinding mill (not shown) is fed by a launder 5 into the feed box 6. A scoop 7 on the rotating part of the mill picks up a charge of ore and Water once in each rotation and discharges the same into the mill chamber through the v.

inlet 4;. The 4modifying agent 1s conveniently fed into a supply tank 8 through a supply pipe and tap 9. The-rotating mill is actuated in any suitable manner, as by a gear wheel 1() fixed upon the rotating part and meshing with suitable drivingv gearing. outlet 3 the finely ground ore and water are delivered intol a launder 11 and thence into the mixer or agitating box 18 of the agitation-froth apparatus, and here a suitable frothing agent'may be fed to the pulp from a second supply tank 12 through a supply pipe and tap 13. In the feed `launder 11 an additional quantity of water may b e added through a Water feed pipe andtap 17 vThe water and ore are usually present in the mill in equal proportions, and the water added inthe feed launder brings the -amount of water up to about three and lone-half to four times the weightl of the ore. Within the mixer or agitation box is arranged to rotatean impeller or agitator 14: to perform its usual function of violently agitating the pulp and beating 'in air, and the agitated the feed box of the mill from From the mill.

pulp flows into a spitzkasten' 15, from which the froth is separated by flotation in the usual manner, discharging into 4a concentratesy launder 16. The tailings from the spitzkasten may be drawn into another agitation box or mixer and theagitaton and froth separation repeated, Yand this repetition of the agitation-froth operation may be made as many times as isdesirable, and the concentrates may also be retreated, -all'as well knownin the `agitation-froth process.

The substances suitable for use as modinol, cresol, amyl-alcohol', amyl-acetate, wood tar oil, woodl alcohol, and the like and the mixtures containing them. These are used in minute quantities, such as from 0.001 'per cent. to 0.1 per cent. on the weight of the ore. These substances, upon agitation with water, bring about an emulsilication of air in the-water, and when thus `agitated in consome way-increase the-selective floatabilty ore and also contribute greatly t'o the eiliciency and economy of the agitation-froth process when the water thus modified and the ore thus ground are subjected to that process.

The frothing agents areany of the mineral frothingagents hitherto employed in the agitation-froth process, or mixtures -of these, generally about 0.002 per cent. to 0.4 per cent. of the weight of. the ore. The irothing agents may be the ysaine material or materials as are used as the'mudifying frothing agent, the lighter part thereof may be of the saine materialsas are used forv the modifying agents and for -the heavier part oleic acid have been found to be suitable.

" The nature and arrangement of the appaing from thisinvention, and in the application of this invention to various ores and under various conditions f the process as "above particularly described may'` be modified without departing vfrom this invention. I claim l v 1. .A process for concentrating ores, which consists in grinding the ore'with water, in the presence of an agent for modifying the water, so thatthe agent modifies the physical the floating mineral.

. 2. A process forconcentrating ores, which consists in grinding the org with water, in the presence of an agent for modifyin the agitating the pulp `to form a froth and separating'the froth.

3. A process for concentrating ores, which fying agents are essential* oils, such as oil of eucalyptus and American turpentine, phe-L tact with the ore as the ore is ground, in

of the mineral or metalliferous part of the` agents. When a mixture is employed as the Texas fuel oil, Russian crude petroleum and ratus used may be varied vwithout departg water, so that the agent modifies the p ysi cal characteristics of the Water, and -then' icol 120 characteristics of the water, and separating consists in grinding the ore with water containing a Water modifyingagent so as to modify the' physical 'characteristics' of the Water, and then adding to the pulpa frothing agent and agitating to form a froth and separating the froth.

4. A process for concentrat' ores, which consists in'grinding the ore Wit water containing ,an air emulsifying agent so as to form an air emulsion, and separating the floating mineral.

5. A proces for concentrati ores, WhichV consists in grinding the ore wit -Water containing' an air emulsifying agent so as to forman air emulsion, and then agitating tfllie pulp to form a froth 'and separating the ot Y 6. A process for concentratin ores, which consists in grinding the ore`wit Water containing an air emulsifying agent so as to form an air emulsion, then adding to the -pulp a frothing agentfand agitating to form a froth and separating the froth.

7 A- process for concentratin ores, Which consists in grinding the ore wit Water con-' taining a Water modifying agent in a proportion not exceeding 0.1 per cent. on the 'weight of the ore so as to modify the physical characteristics .of the Water, and separating the floating mineral.

8. A process for concentrating ores, which consists in grinding the ore with Water containing a Water modifying agent in aproportion not exceeding 0.1 per cent. on the Weight of the ore so as to modify the physi cal. characteristics of the water, and then 40. taining a water modifying agent in aproagitating-the pulp to form a froth and separating .the fro h.

Y 9. A process for concentratin ores, which consists in grinding the ore Wit Water conportion vnot exceeding 0.1 per cent. on the -which consists in grinding the ore with wa-A .Weight of theore so as to modify the physical characteristics of the Water, then adding to the pulp a frothing agent'in a prof portion not exceeding 0.4 per cent. on the a and'separatin the froth. or concentrating ores,

ter containing cresol so las to modify. the physical characteristics of the Water, and separating the oating mlneral. v

11. A `process for concentrating ores, which -consists in grinding the ore with water containing cresol so as to mod1fy the physical characteristics of the water, and

- then agitating the-plulp to form a-froth and separating the 'o't vWater flowin 12. A process. for concentrating ores,

which consists in grinding the ore with wathe ter containing cresol so as to modi 'physical characteristics o f the' Water, then adding to the pulp a, frothing agent andv agi-` tating to form a frothvand separating the .which consists in grinding the ore with Water containing cresol in a proportion not exceeding 0.1 per cent. on the Weight'of the `ore so as to modify the physical characteristics of the Water; and then agitating the pulp tolv form a froth and separating the froth.

15. A process for concentrating ores, which consists in grinding the ore with water containing cresol in a proportion not exceeding 0.1 per cent. on the Weight of the ore so as to modify the physical characteristicsof the Water, then adding to the pulp a frothingvagent in a roportion not exceeding Ogpercent. on t e Weight of the ore, and agitating to form a froth and separating the froth. y

16. A process for concentratin ores, Which consists in grinding the ore with Water containing cresol so as to modify physical characteristics of the Water, then adding turpentinc to the ulp and agitating to form a froth and) separating the froth.

X17. A process for concentrating ores, which consists in grinding the ore with water flowing through the grinding compartment and containing a small proportlon of fa Water modifying agent so as' to modify the physical characteristics ofA the Water, and then separating the floating mineral.

18. 'lhe processv for concentratmg pres, which consists in so grinding `the ore with through the -gfgrinding compartment an containing a small proportion of an air emul'sifying agent` as to form an a1r emulsion, and then separatmg'the floating mineral. d l A lIn testimony v vhereof I *have 'affixed .by signature in presence of two Witnesses.

' GEGRGE A. CHAPMAN.

Witnesses:

HENRY D. WnLIAMs, VICTOR D. BoRs'r.

the 

